.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
.\" SPDX-License-Identifier: GPL-2.0+
.\" %%%LICENSE_END
.TH IOCTL-XFS-FSGETXATTR 2 2019-06-17 "XFS"
.SH NAME
ioctl_xfs_fsgetxattr \- query information for an open file
.SH SYNOPSIS
.br
.B #include <linux/fs.h>
.PP
.BI "int ioctl(int " fd ", XFS_IOC_FSGETXATTR, struct fsxattr *" arg );
.br
.BI "int ioctl(int " fd ", XFS_IOC_FSGETXATTRA, struct fsxattr *" arg );
.br
.BI "int ioctl(int " fd ", XFS_IOC_FSSETXATTR, struct fsxattr *" arg );
.SH DESCRIPTION
Query or set additional attributes associated with files in various file
systems.
The attributes are conveyed in a structure of the form:
.PP
.in +4n
.nf
struct fsxattr {
	__u32         fsx_xflags;
	__u32         fsx_extsize;
	__u32         fsx_nextents;
	__u32         fsx_projid;
	__u32         fsx_cowextsize;
	unsigned char fsx_pad[8];
};
.fi
.in
.PP
.I fsx_xflags
are extended flags that apply to this file.
Refer to the section
.B XFS INODE FLAGS
below for more information.

.PP
.I fsx_extsize
is the preferred extent allocation size for data blocks mapped to this file,
in units of filesystem blocks.
If this value is zero, the filesystem will choose a default option, which
is currently zero.
If
.B XFS_IOC_FSSETXATTR
is called with
.B XFS_XFLAG_EXTSIZE
set in
.I fsx_xflags
and this field set to zero, the XFLAG will also be cleared.
.PP
.I fsx_nextents
is the number of data extents in this file.
If
.B XFS_IOC_FSGETXATTRA
was used, then this is the number of extended attribute extents in the file.
.PP
.I fsx_projid
is the project ID of this file.
.PP
.I fsx_cowextsize
is the preferred extent allocation size for copy on write operations
targeting this file, in units of filesystem blocks.
If this field is zero, the filesystem will choose a default option,
which is currently 128 filesystem blocks.
If
.B XFS_IOC_FSSETXATTR
is called with
.B XFS_XFLAG_COWEXTSIZE
set in
.I fsx_xflags
and this field set to zero, the XFLAG will also be cleared.

.PP
.I fsx_pad
must be zeroed.

.SH XFS INODE FLAGS
This field can be a combination of the following:

.TP
.B XFS_XFLAG_REALTIME
The file is a realtime file.
This bit can only be changed on a file when it has no allocated extents.
.TP
.B XFS_XFLAG_PREALLOC
The file has preallocated space.
.TP
.B XFS_XFLAG_IMMUTABLE
The file is immutable - it cannot be modified, deleted or renamed,
no link can be created to this file and no data can be written to the
file.
Only the superuser or a process possessing the CAP_LINUX_IMMUTABLE
capability can set or clear this flag.
If this flag is set before a
.B XFS_IOC_FSSETXATTR
call and would not be cleared by the call, then no other attributes can be
changed and
.B EPERM
will be returned.
.TP
.B XFS_XFLAG_APPEND
The file is append-only - it can only be opened in append mode for
writing.
For directories, this means that files cannot be unlinked from this directory.
Only the superuser or a process possessing the CAP_LINUX_IMMUTABLE
capability can set or clear this flag.
.TP
.B XFS_XFLAG_SYNC
All writes to the file are synchronous.
If set on a directory and the
.B /proc/sys/fs/xfs/inherit_sync
tunable is set to 1, new files and subdirectories created in the directory
will also have the flag set.
.TP
.B XFS_XFLAG_NOATIME
When the file is accessed, its atime record is not modified.
If set on a directory and the
.B /proc/sys/fs/xfs/inherit_noatime
tunable is set to 1, new files and subdirectories created in the directory
will also have the flag set.
.TP
.B XFS_XFLAG_NODUMP
The file should be skipped by backup utilities.
If set on a directory and the
.B /proc/sys/fs/xfs/inherit_nodump
tunable is set to 1, new files and subdirectories created in the directory
will also have the flag set.
.TP
.B XFS_XFLAG_RTINHERIT
Realtime inheritance bit - new files created in the directory
will be automatically created as realtime files.
If set on a directory, new subdirectories created in the directory will also
have the inheritance flag set.
.TP
.B XFS_XFLAG_PROJINHERIT
Project inheritance bit - new files and directories created in
this directory will inherit the project ID of this directory.
If set on a directory, new subdirectories created in the directory will also
have the inheritance flag set.
.TP
.B XFS_XFLAG_NOSYMLINKS
Disallows creation of symbolic links in the directory.
This flag can only be set on a directory.
If set on a directory and the
.B /proc/sys/fs/xfs/inherit_nosymlinks
tunable is set to 1, new files and subdirectories created in the directory
will also have the flag set.
.TP
.B XFS_XFLAG_EXTSIZE
Extent size bit - if a basic extent size value is set on the file
then the allocator will allocate in multiples of the set size for
this file (see
.B fsx_extsize
below).
The extent size can only be changed on a file when it has no allocated extents.
.TP
.B XFS_XFLAG_EXTSZINHERIT
Extent size inheritance bit - new files and directories created in
the directory will inherit the extent size value (see
.B fsx_extsize
below) of the parent directory.
New subdirectories created in the directory will inherit the extent size
inheritance bit.
.TP
.B XFS_XFLAG_NODEFRAG
No defragment file bit - the file should be skipped during a defragmentation
operation.
If set on a directory and the
.B /proc/sys/fs/xfs/inherit_nodefrag
tunable is set to 1, new files and subdirectories created in the directory
will also have the flag set.
.TP
.B XFS_XFLAG_FILESTREAM
Filestream allocator bit - allows a directory to reserve an allocation group
for exclusive use by files created within that directory.
Files being written in other directories will not use the same allocation group
and so files within different directories will not interleave extents on disk.
The reservation is only active while files are being created and written into
the directory.
If set on a directory, new files and subdirectories created in the directory
will also have the flag set.
.TP
.B XFS_XFLAG_DAX
If the filesystem lives on directly accessible persistent memory, reads and
writes to this file will go straight to the persistent memory, bypassing the
page cache.
If set on a directory, new files and subdirectories created in the directory
will also have the flag set.
This flag cannot be set on filesystems which have the reflink feature enabled.
.TP
.B XFS_XFLAG_COWEXTSIZE
Copy on Write Extent size bit - if a CoW extent size value is set on the file,
the allocator will allocate extents for staging a copy on write operation
in multiples of the set size for this file (see
.B fsx_cowextsize
below).
If set on a directory, new files and subdirectories created in the directory
will have both the flag and the CoW extent size value set.
.TP
.B XFS_XFLAG_HASATTR
The file has extended attributes associated with it.

.SH RETURN VALUE
On error, \-1 is returned, and
.I errno
is set to indicate the error.
.PP
.SH ERRORS
Error codes can be one of, but are not limited to, the following:
.TP
.B EACCESS
Caller does not have sufficient access to change the attributes.
.TP
.B EFAULT
The kernel was not able to copy into the userspace buffer.
.TP
.B EFSBADCRC
Metadata checksum validation failed while performing the query.
.TP
.B EFSCORRUPTED
Metadata corruption was encountered while performing the query.
.TP
.B EINVAL
One of the arguments was not valid.
.TP
.B EIO
An I/O error was encountered while performing the query.
.TP
.B ENOMEM
There was insufficient memory to perform the query.
.TP
.B EPERM
Caller did not have permission to change the attributes.
.SH CONFORMING TO
This API is implemented by the ext4, xfs, btrfs, and f2fs filesystems on the
Linux kernel.
Not all fields may be understood by filesystems other than xfs.
.SH SEE ALSO
.BR ioctl (2),
.BR ioctl_iflags (2)
